Surgical Screw

ABSTRACT

A surgical screw configured to expand and prevent or minimize bone growth inside of the surgical screw is provided. Accordingly, the surgical screw is configured to increase the purchase of the surgical screw with respect to the bone, but also to be withdrawn from the bone without damaging the bone as a result of bone ingrowth. The surgical screw includes a center post with an inner bore and an outer sleeve concentric to the center post. An outer surface of the outer sleeve includes a thread to engage bone. The outer sleeve includes a cut pattern defining an expandable region configurable between a first state with a first radius measured from a longitudinal axis of the surgical screw to the outer surface and a second state having a second radius measured from the longitudinal axis to the outer surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/706,555, filed Sep. 15, 2017, the contents of which are incorporatedherein by reference.

TECHNICAL FIELD

The present disclosure generally relates to a surgical screw configuredto radially expand for use in a spinal procedure.

BACKGROUND

The spine is a flexible column formed of a plurality of bones calledvertebrae. The vertebrae are hollow and stack one upon the other,forming a strong hollow column for support of the cranium and trunk. Thehollow core of the spine houses and protects the nerves of the spinalcord. The different vertebrae are connected to one another by means ofarticular processes, ligaments, and intervertebral, fibrocartilaginousbodies known as disks. Various spinal disorders may cause the spine tobecome misaligned, curved, and/or twisted or result in fractured and/orcompressed vertebrae. It is often necessary to surgically correct thesespinal disorders.

The spine includes seven cervical (neck) vertebrae, twelve thoracic(chest) vertebrae, five lumbar (lower back) vertebrae, and the fusedvertebrae in the sacrum and coccyx that help to form the hip region.While the shapes of individual vertebrae differ among these regions,each is essentially a short hollow shaft containing the bundle of nervesknown as the spinal cord. Individual nerves, such as those carryingmessages to the arms or legs, enter and exit the spinal cord throughgaps between vertebrae. The spine is held upright through the work ofthe back muscles, which are attached to the vertebrae.

The spinal disks act as shock absorbers, cushioning the spine, andpreventing individual bones from contacting each other. Disks also helpto hold the vertebrae together. The weight of the upper body istransferred through the spine to the hips and the legs. Disks maydegenerate, herniate, bulge, or burst and impinge on the nerves betweenthe vertebrae causing pain.

While the normal spine has no side-to-side curve, it does have a seriesof front-to back curves, giving it a gentle “S” shape. If the propershaping and/or curvature are not present due to scoliosis, neuromusculardisease, cerebral palsy, or other disorder, it may be necessary tostraighten or adjust the spine into a proper curvature. Generally thecorrect curvature is obtained by manipulating the vertebrae into theirproper position and securing that position with a rigid system ofscrews, rods, intervertebral spaces, and/or plates. The variouscomponents of the system may be surgically inserted through open orminimally invasive surgeries. The components may also be insertedthrough various approaches to the spine including anterior, lateral, andposterior approaches and others in between.

Some screws may be expandable in order to enhance stability within thevertebra, for example when the vertebra suffers from degeneration,osteoporosis, and other conditions that cause the bone to becomebrittle. These expandable bone screws may allow bone ingrowth throughexpanded cells of the screw. In some instances such as revisionsurgeries, it may be necessary to remove the expanded screw. However,once the bone becomes mineralized, it reduces the ability of theexpanded cells to collapse back to the base diameter of the screw.

SUMMARY

Provided herein are expandable surgical screws and methods forpreventing bone ingrowth inside the surgical screw. A surgical screwincludes generally a center post. The center post is a generallyelongated inner member with an inner bore. The surgical screw furtherincludes an outer sleeve concentric to the center post. The outer sleeveincludes a cut pattern. A head is disposed on a proximal end of thecenter post. The head includes a through-hole open to the bore of thecenter post.

The center post extends along a longitudinal axis of the outer sleeve.An outer surface of the outer sleeve includes a thread to engage bone.The cut pattern defines an expandable region configurable between afirst state with a first radius measured from the longitudinal axis tothe outer surface and a second state having a second radius that islarger than the first radius measured from the longitudinal axis to theouter surface.

The head is coupled to the center post at a neck. The through-hole ofthe head is configured to receive a driving instrument to insert anddrive the surgical screw into the bone. The instrument is furtherconfigured to drive the center post and outer sleeve towards the distalend of the surgical screw so as to actuate the cut pattern, wherein theexpandable region moves from the first state to the second state.

In one embodiment, the cut pattern defines a plurality of generallyspear shaped portions in the outer sleeve. The spear shaped portions areformed into a first group and a second group, wherein each of thepointed ends of the first and second group face each other and areaxially offset from each other.

In one embodiment, the distal end of the surgical screw may includecut-outs. The cuts-outs define a first planar surface and a secondplanar surface. The first and second planar surfaces are generallyorthogonal to each other.

In other features, the cut patterns include a first elongated slitopposite a second elongated slit so as to define a first and a secondside of the spear shaped portion. The ends of the first and secondelongated slits come together so as to form a pointed end. The spearshape portion includes a rounded end spaced apart from the pointed endso as to form a pocket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of one embodiment of the surgical screw.

FIG. 2A is a cross-sectional view of the surgical screw shown in FIG. 1taken along line 2-2 in a first state.

FIG. 2B is a cross-sectional view of the surgical screw shown in FIG. 2Ain a second state.

FIG. 3 is an exploded view of the surgical screw shown in FIG. 1.

FIG. 4 is a perspective view of a second embodiment of a cut pattern ofa surgical screw.

FIG. 5 is a perspective view of an embodiment of a deploymentinstrument.

FIG. 6A is a cross-sectional view of the surgical screw shown in FIG. 2Awith a deployment instrument engaged in the inner bore of the centerpost.

FIG. 6B is a cross-sectional view of the surgical screw shown in FIG. 6Bshowing the instrument actuating the surgical screw into the secondstate.

FIG. 7 is a perspective view of the surgical screw in a second state.

FIG. 8 is a perspective view of an embodiment of the surgical screwconfigured to prevent bone ingrowth.

DETAILED DESCRIPTION

With reference to FIG. 1, a surgical screw 10 is provided. The surgicalscrew 10 is configured to expand and prevent or minimize bone growthinside of the surgical screw 10. Accordingly, the surgical screw 10 isconfigured to expand radially into bone so as to increase the purchaseof the surgical screw 10 with respect to the bone, but also contract orretract so as to be withdrawn from the bone without damaging the bone asa result of bone ingrowth.

With reference now to FIGS. 1A-3, a surgical screw 10 according to oneembodiment is provided. The surgical screw 10 is a generally elongatedmember having a distal end opposite a proximal end. The words proximaland distal are used herein to denote specific ends of components of thesurgical screw 10. A distal end refers to the end of the surgical screw10 adapted to be inserted into the body of the patient. A proximal endrefers to the end of the surgical screw 10 opposite of the distal end.

The surgical screw 10 includes a center post 12 with an inner bore 14and an outer sleeve 16 concentric to the center post 12. The center post12 is a continuous surface bounding the inner bore 14 and is open at thedistal end.

The outer sleeve 16 is open at the proximal end of the surgical screw 10and includes a second bore 18 for receiving the center post 12. Thesecond bore 18 is dimensioned to sliding fit the center post 12. Inembodiments, the center post 12 is fixedly attached to the outer sleeve16, e.g., via welding, adhesives or the like, such that the center post12 and outer sleeve 16 rotate as a single unit. In other embodiments,the second bore 18 is dimensioned to have an interference fit with thecenter post 12 such that the center post 12 and outer sleeve 16 rotateas single unit. An outer surface 17 of the outer sleeve 16 includes athread 20 to engage bone. The pitch and the angle of the thread 20 shownherein are illustrative and not limiting to the scope of the appendedclaims. It should be appreciated that although a single thread 20 isshown, the surgical screw 10 may be double threaded.

The outer sleeve 16 includes a cut pattern 22. The cut pattern 22 isillustratively shown formed along a mid-portion of the outer sleeve 16.The cut pattern 22 defines an expandable region 24 configurable betweena first state (FIG. 2A) with a first radius r1 measured from alongitudinal axis 1 to an outer surface 17 of the outer sleeve 16 and asecond state (FIG. 2B) having a second radius r2 larger than the firstradius r1 measured from the longitudinal axis 1 to the outer surface 17of the outer sleeve 16. The cut pattern 22 is configured to actuate theouter sleeve 16 so as to move the outer sleeve 16 between the firststate and the second state.

The cut pattern 22 traverses the outer surface 17 of the outer sleeve16, as shown in FIGS. 1 and 3. In one embodiment, the cut pattern 22defines a plurality of generally spear-shaped portions 26 of the outersleeve 16. The cut patterns 22 include a first elongated slit 22 aopposite a second elongated slit 22 b so as to define a first and asecond side of the spear-shape portion 26. The ends of the first andsecond elongated slits 22 a, 22 b come together so as to form a pointedend.

The spear-shaped portions 26 are a generally elongated member having apointed end. The spear-shaped portions 26 are formed into a first group26 a and a second group 26 b, wherein each of the pointed ends of thefirst and second groups 26 a, 26 b face each other and axially offsetfrom each other. The spear-shaped portions 26 have a thicknesscommensurate with the thickness of the outer sleeve 16. In oneembodiment, the spear-shaped portion 26 includes a rounded end spacedapart from the pointed end formed by the first and second elongatedslits 22 a, 22 b so as to form a pocket 28. FIG. 1A also shows that thethread 20 is continuous and extends onto the spear-shaped portions 26.

The cut pattern 22 further defines a plurality of Y-shaped members 30which are interconnected to each other. The Y-shaped members 30 includea stem 32 and a pair of arms 34. The arms 34 extend at an angle from anend of the stem 32 forming the general shape of a “V”. FIGS. 1 and 3show the Y-shaped members 30 in the first state. FIG. 7 shows theY-shaped members 30 in the second state. FIGS. 1, 3 and 7 furtherillustrate how each end of the arms 34 of the Y-shaped members 30 arecontiguous with each other.

With reference now to FIG. 4, an embodiment of the cut pattern 22includes an angled surface 23 a. The angled surface 23 a is formed onthe tip of the end of the spear shaped portions 26. The angled surface23 a is configured to slide underneath an opposing Y-shaped member 30when the outer sleeve 16 is compressed. As such, the Y-shaped members 30are lifted or forced outwardly by the spear-shaped portions 26.

In one example, the cut pattern 22 is formed by a laser. Lasers that maybe used to dispose the cut patterns 22 include pulse lasers such asfemto-second lasers and continuous wave lasers. In other examples, thecut pattern 22 is mechanically cut with a cutting tool.

A head 36 is disposed on a proximal end of the center post 12 andincludes a through hole 38 open to the inner bore 14 of the center post12. The proximal end of the through-hole 38 of the head 36 may bedimensioned so as to receive the working end of an instrument adapted toengage the head 36 so as to push the center post 12 distally into thesecond bore 18 of the outer sleeve 16. In one embodiment, the proximalend of the through-hole 38 is adapted to seatingly engage a nut or anallen wrench which may be used to turn and implant the surgical screw 10within bone material.

The head 36 is coupled to the center post 12 at a neck 40. Thethrough-hole 38 of the head 36 is configured to receive a deploymentinstrument 100 (shown in FIGS. 5-6B) to insert and drive the center post12 into the bone. The deployment instrument 100 is further configured todrive the center post 12 towards the distal end of the outer sleeve 16so as to compress the outer sleeve 16 and actuate the cut pattern 22,wherein the expandable region 24 moves from the first state to thesecond state.

FIG. 3 is an exploded view of the screw. The center post 12 isconfigured to slide into the second bore 18 of the outer sleeve 16. Theneck 40 of the center post 12 includes a lip 42 separating the neck 40from the head 36. The lip 42 extends radially from the outer surface ofthe neck 40.

The center post 12 further includes an elongated tubular portion 44having a diameter which is smaller than that of the neck 40. A radialedge 45 defines an end portion 48 of the center post 12. The end portion48 of the center post 12 is smaller in diameter than the elongatedtubular portion 44 of the center post 12. The inner bore 14 extendsthrough the center post 12 so as to define an open proximal and distalend of the center post 12.

With reference again to FIG. 3 and also to FIGS. 2A and 2B, the centerpost 12 is adapted to slidingly fit within the second bore 18 of theouter sleeve 16. As shown, the axial length of the center post 12, asmeasured from the lip 42 of the neck 40 to the distal end of the centerpost 12, is shorter than the second bore 18. FIG. 2A shows the distalend of the center post 12 being spaced apart from an inner end wall 19of the outer sleeve 16.

FIG. 2A is a cross-section of the surgical screw 10 shown in FIG. 1taken along line 2-2. FIG. 2A shows the inner dimensions of the secondbore 18 when the surgical screw 10 is in the first state. In particular,the second bore 18 of the outer sleeve 16 is configured to engage thecenter post 12 and control or limit the advancement of the center post12 within the second bore 18. In embodiments, the lip 42 engages aproximal end of the outer sleeve 16 to limit the advancement of thecenter post 12 within the second bore 18. In one embodiment, theproximal end of the outer sleeve 16 includes an inner lip 43 so as todefine a head portion 46 and a body portion 49 of the second bore 18.The head portion 46 of the second bore 18 is larger in diameter than thebody portion of the second bore 18.

FIG. 2B is a view of the surgical screw 10 shown in FIG. 2A in thesecond state. The arrow displayed adjacent the proximal end of the screwindicates a load applied to the head 36 of the center post 12. The loadadvances the distal end of the center post 12 into the second bore 18pressing the distal end of the center post 12 into engagement with theinner end wall 19 disposed within the second bore 18 of the outer sleeve16. The advancement of the center post 12 actuates (compresses) theouter sleeve 16 wherein the cut pattern 22 expands the surgical screw 10into the second state.

In one embodiment, the distal end of the outer sleeve 16 may includecut-outs 50. The cuts-outs 50 define a first planar surface 50 a and asecond planar surface 50 b. The first and second planar surfaces 50 a,50 b are generally orthogonal to each other. The cut-outs 50 facilitatethe entry of the surgical screw 10 into bone.

With reference now to FIGS. 5-6B an operation of the surgical screw 10is provided. The surgical screw 10 is shown being actuated by adeployment instrument 100 so as to define a system 200 for performing aspinal procedure. The system 200 is configured to actuate the surgicalscrew 10 between the first state (FIG. 6A) and the second state (FIG.6B). The deployment instrument 100 is configured to compress the outersleeve 16 so as to actuate the cut pattern 22 between the first stateand the second state.

In one instance, the deployment instrument 100 may be used to compressthe outer sleeve 16 so as to actuate the surgical screw 10 from thefirst state to the second state, such as after the surgical screw 10 hasbeen screwed into bone. The radial expansion of the surgical screw 10helps the surgical screw 10 find purchase in the bone material.

In the event the surgeon desires to remove the surgical screw 10, thedeployment instrument 100 may be used to contract or retract the outersleeve 16 from the compressed state, wherein the surgical screw 10 ismoved from the second state to the first state. The screw may then besimply turned and removed from the implant site. For example, inembodiments where the lip 42 of the center post 12 is fixedly attachedto the outer sleeve 16, the deployment instrument 100 may have one ormore retraction pins 110 that may be deployed and extend outwardly fromthe rod 102 via an actuator 112. Also, the center post may have aretraction groove 15 that is complimentary with the one or moreretraction pins 110. Upon insertion of the deployment instrument 100into the surgical screw 10 as depicted in FIG. 6B, the retraction pins110 are deployed (e.g., via an actuator 112) into the retraction groove15 such that unscrewing the deployment instrument 100 from the distalend of the outer sleeve 16 moves the retraction pins 110 and the lip 42fixedly attached to the outer sleeve 16 in the proximal direction.Movement of the lip 42 fixedly attached to the outer sleeve 16 stretchesor de-compresses the expandable region 24 of the outer sleeve 16 back tothe first state.

FIG. 6A shows the deployment instrument 100 inserted into the inner bore14 of the center post 12. In one embodiment of a deployment instrument100, the deployment instrument 100 includes a rod 102 with a threadedend 104 and a handle 106. A collar 108 is disposed a predetermineddistance from the threaded end 104. The collar 108 is fixedly mounted tothe rod 102. FIG. 6A shows the threaded end 104 of the rod 102 adjacenta threaded end 18 a of the second bore 18 of the outer sleeve 16.

FIG. 6B shows the advancement of the deployment instrument 100 into thethreaded end 104 of the second bore 18. The rod 102 may be threaded intothe second bore 18 by simply turning the handle 106. As the rod 102 isthreaded deeper into the second bore 18, the collar 108 applies a loadto the head 36 of the center post 12 pushing the center post 12 furtherinto the second bore 18 of the outer sleeve 16. As the center post 12 ispushed further into the outer sleeve 16, the cut pattern 22 is actuatedfrom the first state to the second state, radially expanding thediameter of the surgical screw 10 about the expansion regions.

FIG. 7 shows how the pointed ends of the spear-shaped portions 26 closethe pocket 28 and abut against the Y-shaped members 30, which compressesthe arms 34 causing the arms 34 to protrude radially from the outersleeve 16. Though FIG. 7 shows the arms 34 of the Y-shaped members 30creating a gap with respect to a respective spear, it should beappreciated that the spear-shaped portions and Y-shaped members 30 maybe dimensioned so as to abut against each other and expand radiallywithout creating any gaps.

With reference now to FIG. 8, an embodiment of a surgical screw 10configured to inhibit bone ingrowth is provided. As used herein, theterm “bone ingrowth” refers to a condition wherein bone growth intrudesinto the gaps shown in FIG. 7. The surgical screw 10 includes a centerpost 12 with an inner bore 14 and an outer sleeve 16 concentric to thecenter post 12. The center post 12 is a continuous surface bounding theinner bore 14 and is open at the distal end. For illustrative purposes,the center post is not shown.

The outer sleeve 16 includes a cut pattern 22. The cut pattern 22traverses the outer surface 17 of the outer sleeve 16. The cut pattern22 defines a plurality of generally spear-shaped portions 26 of theouter sleeve 16. The cut patterns 22 include a first elongated slit 22 aopposite a second elongated slit 22 b so as to define a first and asecond side of the spear-shaped portion 26. The ends of the first andsecond elongated slits 22 a, 22 b come together so as to form thepointed end of the spear-shaped portions 26. The cut pattern 22 furtherdefines a plurality of Y-shaped members 30 which are interconnected toeach other. The Y-shaped members 30 include a stem 32 and a pair of arms34. The arms 34 extend at an angle from an end of the stem 32 formingthe general shape of a “V”.

The cut pattern 22 includes an angled surface 23 a formed on the tip ofthe end of the spear-shaped portions 26. The angled surface 23 a isconfigured to slide underneath an opposing Y-shaped member 30 when theouter sleeve 16 is compressed. FIG. 8 shows how the sides of the end ofthe spear-shaped portions 26 (shown in a broken line) are pressedagainst each other when the surgical screw 10 is compressed. Further theends of the spear-shaped portions 26 slide underneath and are in contactwith a respective arm 34 of the Y-shaped members 30. The spear-shapedportions 26 urge the Y-shaped members 30 radially outward so as to placethe surgical screw in the second state as shown in FIG. 8. The sidewalls of the spear-spear shaped portions 26 are in contact withcorresponding and adjacent stems 32 of the Y-shaped member 30 so as toform a seal 52 which prevents bone ingrowth from occurring. Thus,removal of the surgical screw 10 minimizes damage to the implant siterelative to expandable screws with gaps.

It should be appreciated that the surgical screw 10 may be made from asingle or multiple stainless steel alloy, nickel titanium alloy (e.g.,Nitinol), surgical grade titanium alloy (for example, Ti-6Al-4V, ASTM F136), commercially pure titanium (for example, Ti-CP2, ASTM F 67) withor without an electrolytic conversion coating, cobalt-chrome alloys(e.g., ELGILOY® from Elgin Specialty Metals, Elgin, Ill.; CONICHROME®from Carpenter Metals Corp., Wyomissing, Pa.), nickel-cobalt alloys(e.g., MP35N® from Magellan Industrial Trading Company, Inc., Westport,Conn.), molybdenum alloys (e.g., molybdenum TZM alloy, for example asdisclosed in International Pub. No. WO 03/082363 A2, published 9 Oct.2003, which is herein incorporated by reference in its entirety),tungstenrhenium alloys, for example, as disclosed in International Pub.No. WO 03/082363, polymers such as polyethylene teraphathalate (PET),polyester (e.g., DACRON® from E. I. DuPont de Nemours and Company,Wilmington, Del.), polypropylene, aromatic polyesters, such as liquidcrystal polymers (e.g., Vectran, from Kuraray Co., Ltd., Tokyo, Japan),ultra-high molecular weight polyethylene (i.e., extended chain,high-modulus or high-performance polyethylene) fiber and/or yarn (e.g.,SPECTRA® Fiber and SPECTRA® Guard, from Honeywell International, Inc.,Morris Township, N.J., or DYNEEMA® from Royal DSM N. V., Heerlen, theNetherlands), polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE),polyether ketone (PEK), polyether ether ketone (PEEK), poly ether ketoneketone (PEKK) (also poly aryl ether ketone ketone), nylon,polyether-block co-polyamide polymers (e.g., PEB AX® from ATOFINA,Paris, France), aliphatic polyether polyurethanes (e.g., TECOFLEX® fromThermedics Polymer Products, Wilmington, Mass.), polyvinyl chloride(PVC), polyurethane, thermoplastic, fluorinated ethylene propylene(FEP), absorbable or resorbable polymers such as polyglycolic acid(PGA), poly-L-glycolic acid (PLGA), polylactic acid (PLA), poly-L-lacticacid (PLLA), polycaprolactone (PCL), polyethyl acrylate (PEA)spolydioxanone (PDS), and pseudo-polyamino tyrosine-based acids, extrudedcollagen, silicone, zinc, echogenic, radioactive, radiopaque materials,a biomaterial (e.g., cadaver tissue, collagen, allograft, autograft,xenograft, bone cement, morselized bone, osteogenic powder, beads ofbone) any of the other materials listed herein or combinations thereof.Examples of radiopaque materials are barium sulfate, zinc oxide,titanium, stainless steel, nickel-titanium alloys, tantalum, and gold.

The surgical screw 10 can be filled, coated, layered, and/or otherwisemade with and/or from cements, fillers, glues, and/or an agent deliverymatrix known to one having ordinary skill in the art and/or atherapeutic and/or diagnostic agent. Any of these cements and/or fillersand/or glues can be osteogenic and osteoinductive growth factors.

Examples of such cements and/or fillers includes bone chips,demineralized bone matrix (DBM), calcium sulfate, corallinehydroxyapatite, biocoral, tricalcium phosphate, calcium phosphate,polymethyl methacrylate (PMMA), biodegradable ceramics, bioactiveglasses, hyaluronic acid, lactoferrin, bone morphogenic proteins (BMPs)such as recombinant human bone morphogenetic proteins (rhBMPs), othermaterials described herein, or combinations thereof.

While the invention has been described in connection with variousembodiments, it will be understood that the invention is capable offurther modifications. This application is intended to cover anyvariations, uses, or adaptations of the invention following, in general,the principles of the invention, and including such departures from thepresent disclosure as, within the known and customary practice withinthe art to which the invention pertains.

1. A surgical screw comprising: an outer sleeve, the outer sleeve havinga thread and a cut pattern, the cut pattern defining a plurality offirst and second spear-shaped portions, the plurality of first spearshaped portions extending along an axis of the outer sleeve, each of theplurality of first spear-shaped portions being formed by a pair ofspaced apart first slits so as to define an elongated first bodypointing proximally to a first pointed end and the plurality of secondspear-shaped portions extending along an axis of the outer sleeve, eachof the plurality of second spear-shaped portions being formed by a pairof spaced apart second slits so as to define an elongated second bodypointing distally to a second pointed end, wherein each of the first andsecond pointed ends are axially and radially offset from each other andare disposed along a common radius, the plurality of first and secondspear-shaped portions defining an expandable region, the expandableregion configurable between a first state with a first radius measuredfrom a longitudinal axis of the outer sleeve to an outer surface of theouter sleeve and a second state having a second radius measured from thelongitudinal axis to the outer surface of the outer sleeve, the firstradius being less than the second radius.
 2. The surgical screw of claim1, wherein each first elongated body is axially and radially offset fromeach second elongated body.
 3. The surgical screw of claim 1, whereineach of the first and second pointed ends are located next to each otheron the outer sleeve when the surgical screw is in the first state. 4.The surgical screw of claim 1, wherein the first pointed ends arelocated proximal to the second pointed ends when the surgical screw isin the second state.
 5. The surgical screw of claim 1, wherein each ofthe plurality of first and second spear-shaped portions includes arounded end spaced apart from a respective first and second pointed endsof the cut pattern so as to form a pocket.
 6. The surgical screw ofclaim 5, wherein the cut pattern further defines a plurality of Y-shapedmembers which are interconnected to each other.
 7. The surgical screw ofclaim 6, wherein the plurality of Y-shaped members include a stem and apair of arms, the arms extending at an angle from an end of the stemforming the general shape of a “V”.
 8. The surgical screw of claim 1,further comprising a center post having an inner bore, the outer sleevebeing concentric to the center post, wherein the center post furtherincludes a head and a neck, the head including a through-hole open tothe inner bore of the center post.
 9. The surgical screw of claim 8,wherein the neck of the center post includes a lip separating the neckfrom the head, the lip extending radially from an outer surface of theneck.
 10. A system for performing a spinal procedure, the systemcomprising: the surgical screw of claim 1; and a deployment instrument,the deployment instrument configured to compress or retract the outersleeve so as to actuate the cut pattern between the first state and thesecond state.
 11. The system as set forth in claim 10, wherein thedeployment instrument includes a rod with a threaded end, a handle and acollar disposed a predetermined distance from the threaded end.
 12. Thesystem of claim 11, wherein the outer sleeve comprises a second borewith a threaded end configured to receive the threaded end of the rod.13. The system of claim 12, wherein each of the plurality of first andsecond spear-shaped portions includes a rounded end spaced apart from arespective first and second pointed ends of the cut pattern so as toform a pocket.
 14. The system of claim 13, wherein the cut patternfurther defines a plurality of Y-shaped members which are interconnectedto each other.
 15. The system of claim 14, wherein the plurality ofY-shaped members include a stem and a pair of arms, the arms extend atan angle from an end of the stem forming the general shape of a “V”. 16.The system of claim 14, wherein the surgical screw further comprises acenter post with an inner bore, the outer sleeve concentric to thecenter poster, and wherein the center post includes a head and a neck,and the head includes a through-hole open to the inner bore of thecenter post.
 17. A surgical screw comprising: a center post having aninner bore; an outer sleeve concentric to the center post, the outersleeve having a thread and a cut pattern, the cut pattern defining anexpandable region, the cut pattern including a slit defining a pluralityof spear shaped portions nested between a plurality of Y-shaped members,the plurality of Y-shaped members being interconnected to each other,the expandable region configurable between a first state with a firstradius measured from a longitudinal axis of the outer sleeve to an outersurface of the outer sleeve and a second state having a second radiusmeasured from the longitudinal axis to the outer surface of the outersleeve, wherein compression of the outer sleeve relative to the centerpost actuates the cut pattern so as to move the surgical screw betweenthe first state and the second state, wherein an edge of one of theplurality of spears at least partially abuts an edge of an opposite oneof the plurality of spears.
 18. The surgical screw of claim 17, whereinfully compressing the outer sleeve relative to the center post causesthe edges of the plurality of spears to be seated beneath a portion of acorresponding one of the Y-shaped members so as to form a seal to reducebone ingrowth
 19. The surgical screw of claim 17, wherein each of theplurality of spear-shaped portions includes a rounded end spaced apartfrom a pointed end of the cut pattern so as to form a pocket.
 20. Thesurgical screw of claim 17, wherein the plurality of Y-shaped membersinclude a stem and a pair of arms, the arms extending at an angle froman end of the stem forming the general shape of a “V”.